1. Field of the Disclosure
The disclosure relates to structures and formation methods of memory devices, and in particular to structures and formation methods of resistive random-access memory (RRAM) devices.
2. Description of the Related Art
Recently, a variety of electronic products have become popular, which largely increases the demands for non-volatile memory devices. The flash memory device is the mainstream of the non-volatile memory technology. However, since device sizes continue to shrink, the flash memory device has encountered issues such as high operation voltage, slow operation speed, and bad data retention. As a result, the future development of the flash memory device is limited.
Therefore, many materials and apparatus of new non-volatile memory devices are under development. The new non-volatile memory devices include, for example, magnetic random access memory (MRAM) devices, phase change memory (PCM) devices, and resistive random access memory (RRAM) devices. Among the non-volatile memory devices, the RRAM devices have many advantages such as low power consumption, low operation voltage, short writing-in and erasing time, high reliability, long retention time, non-destructive read-out, multi-state memory, process simplicity, and requiring only a small area.
However, the yield and the operation of the RRAM devices still need to be further improved.